1. Field of the Invention
The invention relates to a variable intake apparatus for a V-type internal combustion engine, such as a V-eight engine. More specifically, the invention relates to an arrangement of a plurality of valves provided in a variable intake apparatus and a drive mechanism thereof.
2. Description of the Related Art
Generally, a variable intake apparatus for a V-type internal combustion engine in which each of intake pipes is separated from a surge tank by a partition wall is provided. In the variable intake apparatus, communication ports are provided in the partition wall for the respective intake pipes, and opened and closed by respective variable intake valves to adjust the length of intake passages.
For example, Japanese Patent Publication No. 8-9969 describes a technology with respect to such a variable intake apparatus in which a plurality of variable intake valves are arranged in one row, and integrally connected to a single turning shaft. In the variable intake apparatus, the turning shaft is turned by an actuator such that the variable intake valves synchronously open and close the respective communication ports.
However, in the above-described variable intake apparatus, the variable intake valves are arranged in one row, and therefore the length of the variable intake apparatus in the direction in which the variable intake valves are arranged may need to be long enough to accommodate the required number of the variable intake valves. This may increase the size of the variable intake apparatus.
Moreover, if all the variable intake valves are arranged in one row, there is a restriction on the diameter of each valve. Due to this restriction, the requirement for the valve diameter to achieve the desired performance may not be satisfied.